docs: def get_config_set(self, section, option):
  		"""Returns a set with each value per config file in it.
  		"""
  		values = set()
  		for cp, filename, fp in self.layers:
  			filename = filename # pylint
  			fp = fp # pylint
  			if cp.has_option(section, option):
  				values.add(cp.get(section, option))
  		return values